is i possible to fit a STRAT pickguard that can only fit a humbucker on my yamaha pacifica? maybe, because they have identical dimensions.
well yeah, but wouldn't you have a gap where the humbucker should be that is just filled with a single coil?
If your looking for a pickguard that only has a cut out for a single humbucker. Yes they are available. Stewmac might have one and warmoth will make one.
No, the pacifica has a smaller body and a different route. You could make it fit but it's really not worth the effort at all.